Ecosystem Carbon Allocation of a Temperate Mixed Forest and a Subtropical Evergreen Forest in China

Ecosystem carbon allocation can indicate ecosystem carbon cycling visually through its quantification within different carbon pools and carbon exchange. Using the ecological inventory and eddy covariance measurement applied to both a mature temperate mixed forest in Changbai Mountain (CBM) and a mature subtropical evergreen forest in Dinghu Mountain (DHM), we partitioned the ecosystem carbon pool and carbon exchange into different components, determined the allocation and analyzed relationships within those components. Generally, the total carbon stock of CBM was slightly higher than that of DHM due to a higher carbon stock in the arbor layer at CBM. It was interesting that the proportions of carbon stock in vegetation, soil and litter were similar for the two mature forests. The ratio of vegetation carbon pool to soil carbon stock was 1.5 at CBM and 1.3 at DHM. However, more carbon was allocated to the trunk and root from the vegetation carbon pool at CBM, while more carbon was allocated to foliage and branches at DHM. Moreover, 77% of soil carbon storage was limited to the surface soil layer (0-20 cm), while there was still plentiful carbon stored in the deeper soil layers at DHM. The root/shoot ratios were 0.30 and 0.25 for CBM and DHM, respectively. The rates of net ecosystem productivity (NPP) to gross ecosystem productivity (GPP) were 0.76 and 0.58, and the ratios of ecosystem respiration (Re) to GPP were 0.98 and 0.87 for CBM and DHM, respectively. The net ecosystem carbon exchange/productivity (NEP) was 0.24 t C ha^-1 yr^-1 for CBM and 3.38 t C ha^-1 yr^-1 for DHM. Due to the common seasonal and inter-annual variations of ecosystem carbon exchange resulting from the influence of environmental factors, it was necessary to use the long record dataset to evaluate the ecosystem sink capacity.     

Relationships between Genetic Diversity of Vascular Plant Species and Climate Factors

Genetic diversity is crucial for plants to respond to global climate change, and exploring relationships between genetic diversity and climatic factors may help predict how global climate change will shape the genetic diversity of plants in the future. So far, however, the extent and magnitude of the impact of climatic factors on the genetic diversity of plants has not been clarified. We collected data from 68 published papers on two widely used measures of genetic diversity of populations (average expected heterozygosity (He) and average observed heterozygosity (Ho)) and on localities of populations of 79 vascular plants, and extracted data on 19 climatic factors from WorldClim. We then explored the relationships between measures of genetic diversity and climatic factors using linear regressions. He of plant populations was significantly correlated with climatic factors in 58.7% (44) of the 75 species that used He as a measure of genetic diversity, and Ho was correlated with climatic factors in 65.1% (41) of the 63 species that used this genetic diversity measure. In general, Mean Temperature of Wettest Quarter, Precipitation Seasonality, Precipitation of Driest Quarter and Temperature Seasonality played a vital role in shaping He, and Ho was mostly correlated with Precipitation of Warmest Quarter, Mean Temperature of Wettest Quarter, Precipitation of Driest Quarter and Precipitation of Driest Month. Also, the proportion of the significant correlations between genetic diversity of populations and climatic factors was higher for woody than for herbaceous species, and different climatic factors played different roles in shaping genetic diversity of these two growth forms. Our results suggest that climate may play an important role in shaping genetic diversity of plant populations, that climatic change in the future may alter genetic diversity of plants, and that genetic diversity of different plant forms may respond to climatic change differently.     

WRF模式对青藏高原那曲地区大气边界层模拟适用性研究

采用WRF（Weather Research and Forecasting）模式4种边界层参数化方案对青藏高原那曲地区边界层特征进行了数值模拟,并利用"第三次青藏高原大气科学试验"在青藏高原那曲地区5个站点的观测资料对模拟结果进行验证,分析不同参数化方案在那曲地区的适用性。研究表明,YSU、MYJ、ACM2和BouLac方案对2 m气温和地表温度的模拟偏低。BouLac方案模拟的地表温度偏差较小。通过对能量平衡各分量的对比分析发现,温度模拟偏低可能是向下长波辐射模拟偏低以及感热通量和潜热通量交换过强导致的。对于边界层风、位温和相对湿度垂直结构的模拟,局地方案的模拟效果均优于非局地方案。BouLac方案对那曲地区近地层温度、边界层内位温和相对湿度的垂直分布模拟效果较好。      

天津地面相对湿度资料的非均一性检验及订正

研究中利用NCEP/DOEAMIP-ⅡReanalysis(R-2)比湿再分析资料和基础观测资料两种参考序列,对天津历史月平均相对湿度数据中存在的非均一性因素进行了检验和订正。结果显示,有9个地面站的相对湿度序列存在显著断点,占台站总数的69%。查阅台站元数据得到导致其突变的主要原因是自动站业务化,其次为迁站和仪器变更。从订正量来看,负订正量比例约占96. 3%,其中分布范围在-5.0%～-1.5%,约占总订正量的80%以上。对比分析订正前后月平均相对湿度序列的方差和趋势变化,均一性订正基本修正了非均一性因素造成的突变影响,减缓相对湿度序列长期出现异常偏干的趋势变化。同时,与朱亚妮等(2015)研制的同类数据产品误差分析发现,两类数据的误差平均值较小,但由于一些主观因素影响使得个别台站MAE、SE误差值达到3. 0%以上,造成MAE、SE误差值范围在0～2%的台站比例分别仅在84. 6%和76. 9%及两者以上。从而,一定程度上能够反映出本研究所采用的数据处理技术手段相对以往具有优越性。     

北印度洋-南海季风区热带海洋极端波候变化特征

利用1979—2016年ERA-Interim有效波高（SWH）和海表风场数据,分析了南海-北印度洋极端海浪场分布和变化.结果表明：南海-北印度洋极端SWH分布和极端风速分布形态以及年际变化趋势高度一致,说明了涌浪为主的北印度洋和风浪为主的南海一样,极端SWH都由局地的极端风速控制;强极端SWH主要分布在阿拉伯海以及南海北部,阿拉伯海北部增长与该区域气旋强度增强有着密切关系,而南海的极端SWH主要受东北季风控制;东非沿岸极端SWH线性增长趋势则与索马里急流的年代际尺度上有逐渐增强的线性趋势有关.北印度洋及南海海域极端SWH距平场的EOF分析结果表明,南海极端SWH与北印度洋表现出反相变化的特征.北印度洋（南海海域）极端SWH多出现在西南季风（东北季风）期间,因为在西南季风（东北季风）期间,极端风速也相对增强.     

临沂市海绵城市建设中雨水回收系统设计:以东风东关片区改造为例

以山东省临沂市东风东关片区改造为例,将海绵城市建设要求融入到园林景观建设中。通过对临沂当地降雨量的分析,制定区域降雨控制管理目标,采取了屋顶绿化、透水铺装、下凹式绿地、植草沟、渗井渗管、车库顶板处理、雨水回收利用系统和植物绿化等措施。雨水回收利用系统工程完成后,通过夏季的几场大到暴雨的检验,实现降雨后片区道路雨水下渗明显、无积水,基本达到规划设计的目标要求,该方法将有助于海绵城市在临沂市的推广应用。     

京津冀地区人口与经济协调发展关系研究

京津冀地区是中国重要的人口集聚区和经济增长极,在京津冀协同发展的背景下研究京津冀地区人口与经济的协调发展关系,对于促进区域内经济的可持续发展具有重要意义。本文基于京津冀地区2000-2010年各区(县)和2000-2014年各城市的人口、GDP数据,运用人口—经济增长弹性、地理集中度、不一致指数、重心分析等方法探究京津冀地区人口与经济的协调发展关系,结果表明：①在总量规模上,京津冀地区整体人口增长与经济增长的协调度较高,但各城市人口增长与经济增长的协调度存在较大差异。②在空间分布上,从地理集中度来看,京津冀地区人口、经济地理集中度均呈现北部低、中南部高的分布特征,其中北京、天津经济地理集中度高于人口地理集中度,河北多数城市人口地理集中度高于经济地理集中度;从重心来看,京津冀地区整体的人口与经济重心都向东北方向移动,且经济重心的移动幅度大于人口重心,2个重心偏离距离不断加大,此外各城市的人口重心与经济重心也出现不同程度的分离。最后,提出了促进京津冀地区人口与经济协调发展的政策建议。     

环境WiFi能量采集系统的匹配网络与整流电路设计

设计了一款针对WiFi信号的环境能量采集系统,工作频率范围从2.4 GHz到2.485 GHz.该系统采用了4倍压整流电路,并设计了从天线到整流电路的宽带匹配电路,提升了能量采集的效率.设计的宽带匹配电路在WiFi工作频率范围内,S₁₁均小于-10 dB.整流电路可将采集信号增加4倍,能有效提高RF-DC转换效率.测试结果表明,所设计的电路达到了设计要求,在-10 dBm的输入功率下,达到了40%的RF-DC转换效率,并使超级电容在30 min内采集到了257 mV的电压.     

珠江口湾区海岸线及沿岸土地利用变化遥感监测与分析

利用遥感、GIS技术对珠江口湾区1960~2012年海岸线以及海岸带土地利用进行监测,通过定量化、空间化方法监测海岸线和土地利用的时空变化,并分析二者的关系,进而探究珠江口湾区海岸线变迁的原因。研究结果表明,1960~2012年,珠江口湾区海岸线长度由1 134.95 km增至1 508.02 km,在此期间,湾区新增的陆地面积为878.11 km²;从空间上看,广州、珠海及深圳市在珠江口五市中不仅海岸线增长幅度较显著,新增陆地面积也较大; 1960~2012年,珠江口湾区建设用地扩张幅度非常大,增长了33.05倍,城镇建设和农业发展等人类活动是52 a来珠江口湾区海岸线发生显著变化的重要原因。     

基于灰色关联度的AHP权重矩阵构建方法改进及在农地评价中的应用

合理确定评价指标的权重是准确测度农业土地资源可持续利用能力的关键所在。本文依据灰色关联度对层次分析法(AHP)中判断矩阵的构建方法进行了改进,并获取各项评价指标的权重。在此基础上,分别采用多目标线性加权函数综合评价模型和障碍因子诊断模型,对2001-2012年湖北省枣阳市的农业土地资源可持续利用水平及其制约因素进行评估和辨析。结果显示：基于灰色关联分析法(GRA)改进后的AHP方法在确定指标权重时不仅能有效降低主观赋权的影响,也可避免熵值法等客观赋权法所存在的弊端;地均农业生产总值、人均耕地面积、化肥使用强度、有效灌溉面积、年降水量、人均GDP和农村居民家庭人均纯收入是制约枣阳市农业土地资源可持续利用的最主要因素,但在不同年份各因素的阻碍度表现不一。2001年以来,枣阳市农业土地资源利用的社会经济可持续性水平较高,综合可持续利用水平指数整体上呈增加的态势;但在生态可持续方面,2006年之后不仅明显低于之前年份,而且也显著低于同时期的社会经济可持续性。